I think it's instantaneous indexing, of at least the first page, if you have robots.txt set up correctly. You can test it to try to see how long it takes the first indexing (with the new titles if it's already indexed) by searching Google for: site:yoursite.com
However, the question is about Google Search Console reporting data. I find that it takes 48-96 hours before any reporting is updated for you to see after submitting the sitemap, etc., and it's very minimal as to what's shown. It takes about a week to two to get real useful data flowing in. But, if you have Analytics, you can get an idea of what you'll see almost immediately such as where traffic is coming from at a minimum, as Search Console lags behind it since Analytics reports in Real Time while Search Console has to aggregate keywords, pages, clicks, impressions, etc.